The Pathology Core provides research support and development for the program project grant as a whole. This work is conducted by four faculty, highly experienced and published in marrow transplantation hematopathology, immunopathology, and infectious disease. Graft-versus- host disease (GVHD) studies are carried out in protocols involving skin, liver and gut studies. The methods and panels of antibodies are being evaluated for studies of the pathogenesis of GVHD with novel antibodies to new cellular subtypes, with new confocal microscopic methods, and with antibodies to cytokines and proliferation markers. The aplastic anemia studies are primarily involved with improving the methodology of frozen sections of bone marrow for immunohistological study of infiltrating cellular subtypes and cytokines in the examination of the pathogenesis of aplastic anemia and in elucidating normal immunoanatomy or immunomorphology of bone marrow which necessarily precedes the analysis of the pathologic states. The infectious studies involve the development and application of new methods of diagnosing viral infections with panels of antibodies, new in situ hybridization methods and newer methods of employing single-stranded probes for the evaluation of pathogenesis and diagnosis of viral infections. Pathology also carries out the histology for the canine studies, myelodysplasia project, all of the biopsies for diagnosis and pathogenetic study of GVHD, and the marrow examinations. The group also carries out all the research autopsies necessary for evaluation of the patients receiving ATG therapy and marrow transplantation who do not survive. Autopsies carried out at other institutions are coordinated and reviewed retrospectively by the staff also.